CrFeAlTi复合涂层抗高温氧化及耐铅铋合金腐蚀性能

High-temperature Oxidation Resistance and Corrosion Resistance of CrFeAlTi Composite Coatings

采用热喷涂-激光复合工艺在304不锈钢基体上制备3种CrFeAlTi复合涂层。采用氧化增重法评定涂层和基材抗高温氧化性能;利用光学显微镜(OM)、扫描电子显微镜(SEM/EDS)和X-射线衍射仪(XRD)对涂层微观组织结构进行分析,并对涂层耐液态铅铋合金(LBE)腐蚀性能进行研究。结果表明,3种CrFeAlTi复合涂层均具有良好的抗高温氧化性和耐液态铅铋合金腐蚀性,未加入304不锈钢粉末制备的涂层相对更好;750℃和850℃下氧化3h后304基材增重量分别为0.70g/m2和0.88g/m2,而涂层增重量在850℃也仅有0.074g/m2;450℃和550℃下腐蚀300h,Pb元素沿基材表面向内部的扩散深度达到了8μm和10μm,而在涂层中几乎无扩散,涂层具有很好的抗腐蚀性,能阻止液态铅铋合金扩散到内部,对基材起到一定的防护作用。

Three CrFeAlTi composite coatings were prepared on 304 stainless steel substrate through the combined tech- niques of thermal spraying and subsequent laser sintering. The oxidation weight increase method was adopted to evaluate the high-temperature oxidation resistance property of the coatings and substrate. The microstructure and the corrosion resistance of the coatings to the liquid lead-bismuth eutectic （LBE） alloy were investigated by optical microscopy （OM）, scanning electron microscopy （SEM/EDS） and X-ray diffraction （XRD）. The results show that three CrFeAlTi composite coatings have good high temperature oxidation resistance and corrosion resistance to liquid lead-bismuth alloy, among which the one without the addition of 304 stainless steel powder is relatively better. After an oxidation time for 3 h at 750℃ and 850℃, the mass increment for the 304 substrate are 0.70 g/m^2 and 0.88 g/m^2 respectively, but for the coating is only 0.074 g/m^2 at 850℃. This suggests that the high temperature oxidation resistance of the coatings is better than that of the substrate. After an immersion time for 300 h at 450℃ and 550℃, the diffusion depth of the element Pb reaches about 8μm and 10μm for the 304 substrate, which is rarely detected in coatings. The substrate thus has excellent corrosion property, which can prevent the spread of the liquid corrosive media and play a vital role in preventing the corrosion of materials.